Econundrum: A Greener Commute

Considering how much car travel affects a person's carbon footprint , I'm always looking for ways to cut down on my driving time. Luckily for me, the commute isn't a problem, since a rapid-transit train whisks me under the San Francisco Bay practically to MoJo HQ's doorstep every day. But if you don't live near public transportation or a bike-friendly commute (and you don't happen to have an extra 25 grand kicking around for a Prius), you're probably going to have to get creative.

One idea: Get a GPS device. The technology company Navteq recently found that German drivers who were given navigational devices with real-time traffic information increased their fuel economy by an average of 12 percent. The researchers calculated that GPS systems could save 2,006 pounds of carbon per driver per year, a 24 percent reduction from current emissions levels.

An ABC poll estimated the average American commute at 16 miles one way, creating about 29.3 pounds of CO2 round-trip every day. According to the Navteq researchers' findings, then, getting a GPS device is the same as not driving to work 68 days every year.

A caveat: Since Navteq, the company behind the study, sells software to GPS manufacturers, it has a vested interest in touting the benefits of navigational systems. Still, some independent traffic-savvy types told me they think that the study is solid, if taken with a few grains of salt. First, the study was conducted in Germany—and any American who's been to Europe knows that US freeways take crowded to an entirely different level. Another problem: Once everyone starts using the alternate route that a GPS suggests, it's, well, no longer an alternate route. "The impact for any one driver may be somewhat smaller if more people use these devices and start to clog up alternate routes," said Tai Stillwater, a graduate student who studies traffic and sustainability at the University of California-Davis.

If you don't want to shell out for a GPS (they run about $150-$200), consider these fuel efficiency tips. You can also talk to your boss about telecommuting a few days a week. And for advice on whether to junk your clunker in favor of a hybrid, read our piece on the subject here.